Backlight unit and method for controlling temperature thereof

A backlight unit for effectively controlling a heat absorption operation required under a high temperature condition and a heat emission operation required under a low temperature condition to increase lamp performance and lamp lifespan, and achieve an enhanced initial brightness increase effect includes: a cover bottom including a first portion, a second portion spaced apart from the first portion, and a third portion connecting the first and second portions; a lamp arranged at the first portion of the cover bottom; and a current direction controller connected to the first and second portions and adapted to control a direction of current supplied to the cover bottom according to a Thomson's coefficient of the cover bottom. A method for controlling a temperature of a backlight unit includes controlling the direction of current supplied to the cover bottom according to a Thomson's coefficient of the cover bottom to emit or absorb heat.